512 



SCIENTIFIC RECREATIONS. 



Fig. 561. Telescopic appearance of the Moon. 



we perceive upon its surface dark and light tracts called " seas," though 



they are dried up now. Thus we 

 hear of the " Sea of Serenity/' the 

 " Sea of Storms," and the " Sea of 

 Tranquillity" ; and in the map upon 

 a subsequent page you may see the 

 names of the seas, mountains, and 

 the general formations of the sur- 

 face of the moon. Maps of the 

 moon are now to be procured, 

 though no personal visits can be 

 made to the satellite. It is very 

 interesting to observe or to read 

 about the structure of the moon, 

 for we may thus learn how similar 

 the earth and her attendant are in 

 formation; but one important agency 

 that of water has made a con- 

 siderable difference in tne appearance of the formations. In the moon we 

 have mountains, plains, and rugged craters ; the surface is not level, because 

 the sunlight is visible sooner at some points than others. The chief 

 mountain chain is the Apennines, and has a great elevation ; many traces of 

 volcanic agency are discoverable amid the great desolation, and awful 

 silence reigns throughout. 



As is well known, water has a great erosive power, and its action dis- 

 integrates the surface of the earth with rapid persistency. So the physical 

 appearance of the globe has become much changed in the course of ages : 

 ravines exist where plains used to extend, and rivers cut their way through 

 deep gorges to the sea. The sands and other deposits are overlaid, and thus 

 the whole outward appearance has been altered. Not so the moon. With a 

 very attenuated atmosphere without clouds or rain, there is no moisture, 

 no lake, no water in the moon now. What may have been we can only 

 conjecture. If there ever have been lakes or seas they have all been 

 absorbed. 



The heat upon one side of the moon must be very great at one period, 

 and the cold on the opposite side intense, as one 

 would think yet upon this fact authorities differ 

 somewhat. If the moon possess no atmosphere of 

 any kind it would be fearfully cold and extremely 

 hot at intervals, but a surrounding medium, even 

 of very little density, would modify the extremes ; 

 and while we must accept the fact that the tempera- 

 ture varies very much We need not place it above IOO Fig. 562. Formatio^ near Mostig. 



of heat, nor below 20 of cold. So from close obser- LOW power, 



vation and comparison we are enabled to form a very fair opinion of the 



